U.S. patent application number 11/893159 was filed with the patent office on 2009-02-19 for air filtration system.
This patent application is currently assigned to American Standard International Inc. Invention is credited to Robert Beasley, Larry S. Bias, Timothy H. Cauley, John Mark Hagan, Daniel Joseph Mitchell, Cassius J. Mullen, Kristin Lyn Schaefer, Shannon L. Smith, Mark David Woodruff.
Application Number | 20090044703 11/893159 |
Document ID | / |
Family ID | 40019230 |
Filed Date | 2009-02-19 |
United States Patent
Application |
20090044703 |
Kind Code |
A1 |
Bias; Larry S. ; et
al. |
February 19, 2009 |
Air filtration system
Abstract
An intense field dielectric air filtration system includes a
perimeter frame for wall or ceiling mounting at the inlet of a
return air duct for an air conditioning apparatus. A door including
a grille disposed thereon is mounted for movement on the frame
between working and non-working positions for access to an air
filter unit, a pre-filter unit and an intense field particle
charging unit. Contacts on the filter unit and the field charging
unit engage cooperating contacts on an enclosure mounted on the
frame when the door is closed to supply electrical power. An
interlock is provided to interrupt power when the door is moved to
an open position or the grille is removed. A control system
disposed in the enclosure includes user control features accessible
when the door is in an open position. An alternate embodiment
includes a support frame for positioning the filtration system in
ductwork or the like other than a return air inlet.
Inventors: |
Bias; Larry S.; (Flint,
TX) ; Schaefer; Kristin Lyn; (Tyler, TX) ;
Smith; Shannon L.; (Flint, TX) ; Hagan; John
Mark; (Tyler, TX) ; Woodruff; Mark David;
(Tyler, TX) ; Mitchell; Daniel Joseph; (Gilmer,
TX) ; Mullen; Cassius J.; (Whitehouse, TX) ;
Cauley; Timothy H.; (Whitehouse, TX) ; Beasley;
Robert; (Whitehouse, TX) |
Correspondence
Address: |
The Trane Company;Patent Department 12-1
3600 Pammel Creek Road
La Crosse
WI
54601
US
|
Assignee: |
American Standard International
Inc
|
Family ID: |
40019230 |
Appl. No.: |
11/893159 |
Filed: |
August 15, 2007 |
Current U.S.
Class: |
96/66 ; 55/481;
95/2 |
Current CPC
Class: |
B03C 3/12 20130101; B03C
3/74 20130101; B03C 3/82 20130101; B03C 2201/28 20130101; B03C 3/86
20130101 |
Class at
Publication: |
96/66 ; 55/481;
95/2 |
International
Class: |
B03C 3/011 20060101
B03C003/011; B01D 50/00 20060101 B01D050/00; B03C 3/00 20060101
B03C003/00 |
Claims
1. An air filtration system for an air conditioning apparatus, said
air filtration system comprising: a frame adapted to be mounted at
an inlet to an air duct; a support member mounted on and for
movement relative to said frame between a working position and a
non-working position, said support member including an air inlet
grille disposed thereon; a filter unit mounted on said support
member and operable to generate a high voltage electric field for
collecting particles on said filter unit from an airflow stream
flowing therethrough; and a high voltage electric field charging
unit mounted on said support member upstream from said filter unit
with respect to the direction of air flowing through said air
filtration system.
2. The air filtration system set forth in claim 1 including: a
pre-filter unit mounted on said support member upstream of said
field charging unit.
3. The air filtration system set forth in claim 1 wherein: said
support member comprises a door connected to said frame by hinge
means for movement between said working position and said
non-working position.
4. The air filtration system set forth in claim 3 wherein: said
hinge means comprise spaced apart hinges including separable hinge
members, respectively, whereby said door may be pivoted between
said working and non-working positions with respect to said frame
and removed from said frame.
5. The air filtration system set forth in claim 3 including:
manually actuatable latches for latching said door in said working
position and for releasing said door for movement to said
non-working position.
6. The air filtration system set forth in claim 3 wherein: said
filter unit and said field charging unit include electrical contact
members formed thereon and engageable with corresponding electrical
contact members mounted on a control enclosure supported by said
frame.
7. The air filtration system set forth in claim 6 wherein: said
electrical contact members on said control enclosure are spaced
apart in respective pairs of contact members and are operably
connected to a source of high voltage electric potential.
8. The air filtration system set forth in claim 7 including:
insulated cover members disposed on said enclosure and covering
said electrical contact members.
9. The air filtration system set forth in claim 7 wherein: said
cover members include at least spaced apart double walls formed
thereon providing electrical isolation from said electrical contact
members.
10. The air filtration system set forth in claim 1 including: an
enclosure mounted on said frame and supporting a control circuit
and a high voltage power supply for supplying high voltage electric
potential to said filter unit and said field charging unit.
11. The air filtration system set forth in claim 10 including: an
interface mounted on said enclosure including user actuatable
switches for setting selective control parameters for said air
filtration system, said interface being disposed for operation by a
user by moving said support member to a non-working position with
respect to said frame.
12. The air filtration system set forth in claim 10 including: an
interlock associated with said control circuit for interrupting
power to said power supply when said support member is moved from
said working position to a non-working position.
13. The air filtration system set forth in claim 12 wherein: said
interlock includes a reed switch associated with said control
circuit and a magnet supported by said support member for actuating
said reed switch.
14. The air filtration system set forth in claim 10 including: a
switch actuator supported by said support member for engagement
with a switch mounted on said enclosure for energizing and
de-energizing said air filtration system.
15. The air filtration system set forth in claim 10 including:
spaced apart brackets for supporting said enclosure on said frame
between opposed sidewalls and between top and bottom walls of said
frame.
16. The air filtration system set forth in claim 1 wherein: said
filter unit includes a latch member supported thereon and
engageable with a cooperating latch member fixed with respect to
said support member whereby said filter unit may be releasably
retained on said support member.
17. The air filtration system set forth in claim 1 wherein: said
support member comprises spaced apart bracket members forming
respective parallel slots for receiving said filter unit and said
field charging unit to be disposed directly adjacent each
other.
18. The air filtration system set forth in claim 17 wherein: at
least one of said bracket members includes means cooperable with
said filter unit to prevent placing said filter unit on said
support member in any but a predetermined working position of said
filter unit.
19. An air filtration system for an air conditioning apparatus,
said air filtration system comprising: a frame adapted to be
mounted to an air duct; a door connected to said frame by hinge
means for movement relative to said frame between a working
position and a non-working position, said door including an air
inlet grille disposed thereon; a filter unit mounted on said door
and operable to generate a high voltage electric field for
collecting particles on said filter unit from an airflow stream
flowing therethrough; a high voltage electric field charging unit
disposed upstream from said filter unit with respect to the
direction of air flowing through said air filtration system; a
control enclosure mounted on said frame; and said filter unit and
said field charging unit include electrical contact members formed
thereon and engageable with corresponding electrical contact
members on said control enclosure.
20. The air filtration system set forth in claim 19 wherein: said
hinge means comprise spaced apart hinges including separable hinge
members, respectively, whereby said door may be pivoted between
said working and non-working positions with respect to said frame
and removed from said frame.
21. The air filtration system set forth in claim 19 including:
manually actuatable latches for latching said door in said working
position and for releasing said door for movement to said
non-working position.
22. The air filtration system set forth in claim 19 including: a
control circuit disposed on said enclosure including a high voltage
power supply for supplying high voltage electric potential to said
filter unit and said field charging unit.
23. The air filtration system set forth in claim 22 including: an
interface mounted on said enclosure including user actuatable
switches for setting selective control parameters for said air
filtration system.
24. The air filtration system set forth in claim 23 wherein: said
interface is disposed for operation by a user by moving said door
to a non-working position with respect to said frame.
25. The air filtration system set forth in claim 22 including: an
interlock associated with said control circuit for interrupting
power to said power supply when one of said door and said grille is
moved from said working position to a non-working position.
26. The air filtration system set forth in claim 25 wherein: said
interlock includes a reed switch associated with said control
circuit and a magnet mounted on one of said door and said grille
for actuating said reed switch.
27. The air filtration system set forth in claim 19 including: a
switch actuator supported on said door for engagement with a switch
mounted on said enclosure for energizing and de-energizing said air
filtration system.
28. The air filtration system set forth in claim 19 wherein: said
door includes support members thereon for supporting said filter
unit and said field charging unit on said door.
29. The air filtration system set forth in claim 28 wherein: said
filter unit includes a latch member supported thereon and
engageable with cooperating means fixed with respect to said door
whereby said filter unit may be releasably retained on said
door.
30. The air filtration system set forth in claim 19 including: a
prefilter unit mounted on said door upstream of said filter unit
with respect to the direction of air flowing through said air
filtration system for collecting particulates disposed in said
airflow stream.
31. An air filtration system for an air conditioning apparatus,
said air filtration system comprising: a frame adapted to be
mounted to an air duct including a first frame member comprising
spaced apart sidewalls and an interconnecting end wall, and a
perimeter frame member connected to said sidewalls opposite said
end wall; a door assembly mountable on and for movement relative to
said frame between a working position and a non-working position; a
filter unit mounted on said frame and operable to generate a high
voltage electric field for collecting particles on said filter unit
from an air flowstream flowing therethrough; and a high voltage
electric field charging unit mounted on said frame upstream from
said filter unit with respect to the direction of air flowing
through said air filtration system.
32. The air filtration system set forth in claim 31 including: a
pre-filter unit mounted on said frame upstream of said field
charging unit.
33. The air filtration system set forth in claim 31 including: an
enclosure on said door assembly and supporting a control circuit
and a high voltage power supply for supplying high voltage electric
potential to said filter unit and said field charging unit.
34. The air filtration system set forth in claim 31 including:
manually actuatable latches for latching said door assembly in said
working position and for releasing said door assembly for movement
to a non-working position.
35. The air filtration system set forth in claim 34 including:
electrical contact members on said door assembly spaced apart in
respective pairs of contact members and operably connected to a
source of high voltage electric potential.
Description
BACKGROUND OF THE INVENTION
[0001] The filtration of air in interior or indoor spaces has
become important to maintain and improve human health and to keep
interior spaces and furnishings more clean than heretofore
obtainable. An effective type of electrically energized air
filtration system is known as an Intense Field Dielectric (IFD)
filtration system. U.S. Pat. No. 6,749,669 issued Jun. 15, 2004 to
Griffiths et al is directed to an IFD type filtration system. U.S.
Patent Application Publication No. US 2007/0039472 A1, published
Feb. 22, 2007 by Bias, et al. and assigned to the assignee of the
present invention discloses and claims several improvements in IFD
type filtration systems. U.S. Patent Application Ser. No.
11/516,263 filed Sep. 6, 2006, by Woodruff, et al. and also
assigned to the assignee of the present invention discloses and
claims additional improvements in IFD air filtration systems. The
above-referenced patent, patent application publication and pending
patent application are each incorporated herein by reference.
[0002] Additional improvements have been sought in IFD type air
filtration systems including the need to provide a system which can
be mounted on an interior wall or ceiling at the inlet to a return
air duct for an air conditioning apparatus which is circulating air
to an enclosed space. Remotely locating an IFD air filtration
system with respect to the air conditioning apparatus with which it
is associated presents certain problems in mounting the system,
providing certain control features and providing suitable power to
the system. By providing an IFD air filtration system which can be
mounted remote from air conditioning apparatus, greater flexibility
in providing an overall efficient and desirable air conditioning
system is obtained and it is to these ends that the present
invention has been developed.
SUMMARY OF THE INVENTION
[0003] The present invention provides an improved air filtration
system, particularly a system of the so-called Intense Field
Dielectric (IFD) type. In particular, the invention provides an IFD
type air filtration system which is adapted for mounting remote
from air conditioning apparatus with which the filtration system is
associated. More particularly, the invention provides an air
filtration system which is adapted to be mounted at the inlet to a
return air duct leading to the air conditioning system or apparatus
with which the filter is associated.
[0004] In accordance with one important aspect of the present
invention, an air filtration system is provided which includes a
chassis or frame and a door hinged to the frame and comprising an
air inlet grille, the door supporting certain components of the air
filtration system including a field charging unit and a main,
electrically charged, air filter unit which removes particulates
and the like which have received an electrical charge from the
field charging unit. A so-called prefilter unit may or may not be
disposed on the door. The above-mentioned components are
conveniently supported on the grille or door and at least the
pre-filter unit, if used, and the main filter unit are easily
removed from the grille or door for cleaning, repair or
replacement.
[0005] In accordance with another aspect of the present invention
an IFD type air filtration system is provided which includes a
control system enclosure mounted on a frame which is adapted for
mounting on a wall or ceiling and supported by structural members
of the wall or ceiling. The control system is electrically
connected to a field charging unit and a main filter unit when the
grille or door is in a closed or working position with respect to
the chassis or frame and the control system is disconnected from
the field charging unit and the main filter unit when the door or
grille is moved to an open non working position. The control system
and an enclosure therefor includes contact elements which engage
corresponding contact elements on the field charging unit and the
main filter unit when the grille or door is in the closed
position.
[0006] Several features facilitate servicing the filtration system
of the invention including a conveniently actuatable latch for
latching the main filter unit in its working position, an
arrangement to assure that the main filter unit is correctly
positioned and supported on the system, an arrangement of hinges
and latches which facilitate moving the grille or door between open
and closed positions and removal of the grille or door from the
frame. A control box or enclosure for the filtration system is
mounted on the system frame or chassis and includes conveniently
positioned human actuatable controls and indicators, as well as
other elements which will be appreciated by those skilled in the
art.
[0007] Still further in accordance with the invention, an improved
arrangement of electrical contact elements is provided wherein the
contact elements are supported by the system control box or
enclosure for engagement with components which require electrical
power for operation.
[0008] The present invention still further provides an air
filtration system which includes an improved interlock, comprising
a control feature which de-energizes the electrically operated
filter components when the grille or door is moved from a closed
working position to an open non working position. A user interface
or control panel is advantageously mounted on the control box or
enclosure and which is easily accessible by a user of the air
filtration system upon moving the grille or door to its open
position, although the system may be started and stopped by
actuating a push button on the face of the door without moving the
door to an open position.
[0009] The invention yet further provides an air filtration system
adapted for interpositioning in a duct or cabinet of an air
conditioning system and which enjoys many of the advantages of the
embodiment of the system which is adapted for mounting remote from
an air conditioning apparatus.
[0010] Certain features of the invention have been described
generally hereinabove and those skilled in the art will recognize
the advantages and superior features of the invention heretofore
described as well as other important aspects thereof, upon reading
the detailed description which follows in conjunction with the
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a perspective view of an air filtration system in
accordance with the invention mounted at the inlet of a return air
duct for an air conditioning apparatus;
[0012] FIG. 2 is a perspective view of the filtration system
showing FIG. 1 in a so called open position of a door or grille of
the system;
[0013] FIG. 3 is perspective view similar to FIG. 2 illustrating
additional components of the filtration system;
[0014] FIG. 4 is a detail section view taken generally along the
line 4-4 of FIG. 3;
[0015] FIG. 4A is a detail section view taken along the same line
as FIG. 4 showing an alternate embodiment of a latch mechanism.
[0016] FIG. 4B is a detail perspective view of a charging pin for
the field charging unit;
[0017] FIG. 5 is a detail view illustrating certain features of the
system door and how components of the system are supported
thereby;
[0018] FIG. 6 is a perspective view of the primary or main
electrically charged filter unit in accordance with the
invention;
[0019] FIG. 7 is a perspective view similar in some respects to
FIGS. 1 and 3 with the field charging unit and filter units removed
for illustration of their support structure and the door
hinges;
[0020] FIG. 8 is a detail perspective view of one of the door
hinges shown in FIG. 7;
[0021] FIG. 9 is a detail view illustrating one of the latch
mechanisms used to hold the door and grille in a closed
position;
[0022] FIG. 9A is a detail view of an alternate embodiment of a
latch mechanism for the door and grille;
[0023] FIG. 9B is another detail view of the latch mechanism shown
in FIG. 9A;
[0024] FIG. 10 is a perspective view of the control box or
enclosure for the system of the present invention;
[0025] FIG. 11 is a detail front elevation of a user interface or
control panel;
[0026] FIG. 12 is a detail cutaway view showing the relationship
between a user actuatable system start and stop switch and lighting
therefor;
[0027] FIG. 13 is an exploded perspective view of the control box
or enclosure for the control system for the present invention;
[0028] FIG. 14 is a detail exploded perspective view of one of the
contact element support brackets or covers for supporting two of
the four required contact elements for the system of the
invention;
[0029] FIG. 15 is detail composite section view taken generally
along the line 15-15 of FIG. 13;
[0030] FIG. 16 is another detail perspective view of the control
system enclosure illustrating certain features thereof;
[0031] FIG. 17 is a schematic block diagram of the control system
for the air filtration system of the invention;
[0032] FIG. 18 is a perspective view of another embodiment of an
air filtration system in accordance with the invention; and
[0033] FIG. 19 is a perspective view of the system shown in FIG. 18
taken from a perspective opposite that of FIG. 18.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0034] In the description which follows like parts are marked
throughout the specification and drawings with the same reference
numerals, respectively. Certain features of the invention may be
shown in somewhat generalized or schematic form in the interest of
clarity and conciseness.
[0035] Referring to FIGS. 1 and 2, there is illustrated an improved
air filtration system in accordance with the invention and
generally designated by the numeral 20. The air filtration system
20 is adapted to mount on a wall or ceiling including, for example,
a vertical wall 22, FIG. 1, whereby a suitable opening is provided
in the wall for receiving a chassis or frame of the system and
generally designated by the numeral 24 in FIGS. 2 and 3. Those
skilled in the art will recognize that the filtration system 20 may
also be mounted in other positions including in a ceiling or a
non-vertical wall or a panel or within cabinetry or the like, for
example.
[0036] The filtration system 20 is advantageously disposed at the
inlet of a return air duct 21, FIG. 1, and the direction of airflow
through the components of system is as indicated by the arrows 20a
in FIGS. 1, 4 and 5. As shown in FIGS. 2 and 3, the frame or
chassis 24 is preferably of a rectangular perimeter type including
a perimeter flange 26 joined to top and bottom walls 24a and 24b
and opposed sidewalls 24c and 24d and defining a substantial
rectangular opening 25, FIG. 2. Chassis or frame 24 is preferably
dimensioned to fit between wall supporting structural members or so
called studs 27, FIG. 3. Suitable cross members, not shown,
extending between the studs 27 may be provided to engage and
support the top and bottom walls 24a and 24b of frame 24. The frame
24 may be suitably secured to the wall 22 at the structural members
27 using conventional fasteners extending through the walls 24c and
24d as well as the top and bottom walls 24a and 24b.
[0037] Referring further to FIGS. 2 and 3, the air filtration
system 20 includes a door 32 which may be integrally formed with or
separable from a grille 30 having a substantial number of closely
spaced apart generally horizontally extending louvers 31, FIGS. 1
and 4, formed thereon and allowing air to flow therethrough.
Alternatively, the louvers 31 may extend vertically or be replaced
by other means forming openings, such as spaced apart holes. Door
32 is suitably hinged to the frame 24 at flange 26 by spaced apart
hinges 29, see FIG. 7, for movement between a closed working
position shown in FIG. 1 and the non working door open positions
shown in FIGS. 2, 3 and 7, for example.
[0038] Door 32 includes a rectangular opening 33 formed therein.
Grille 30 may be secured to door 32 by suitable snap fit features,
not shown, or by conventional fasteners, if desired. Door 32
supports and may be integrally formed with opposed spaced apart
parallel somewhat channel shaped support members, or brackets, 34
and 35, FIGS. 2, 3 and 7, which are adapted to support three major
filter components including a main, electrically powered, filter
unit 36, an electrically powered element generally known as a field
charging unit 38, and a pre-filter 40, which may be a conventional
impingement type air filter. Moreover, the filter unit 36 and the
field charging unit 38 may be constructed substantially like the
corresponding filter unit and field charging unit disclosed in U.S.
Patent Application Publication No. US 2007/0039472 A1. The filter
unit 36 and the field charging unit 38 may also embody features of
the corresponding elements disclosed in U.S. Pat. No.
6,749,669.
[0039] Although the field charging unit 38 is constructed
substantially like that described in Patent Application Publication
No. US2007/0039472 A1, certain improvements have been developed
with respect to certain components of the field charging unit. As
described also in the aforementioned Patent Application
Publication, the field charging unit 38 includes a frame 38a having
a handle 38c formed thereon. Frame 38a supports a so called earth
plate 38d, FIG. 4, and provided with plural spaced apart openings
38e, one shown in FIG. 4. An array of conductor pins 38f, one shown
in FIG. 4, is mounted on frame 38a disposed such that a pin 38f is
aligned with each of the openings or holes 38e.
[0040] Conductor pins 38f are preferably formed of a tungsten
composition and are secured to respectively elongated conductor
bars 38g, a portion of one shown in FIG. 4B. Each pin 38f may be
secured to a conductor bar 38g by short clamp member 38h by
suitable means, such as spot welding operations, for example. Still
further, it is desirable to minimize electrical arcing by and
corrosion of the conductors of the field charging unit by
encapsulating the conductor bars 38g with a suitable coating, such
as a high voltage insulating polymer, for example, and indicated by
numeral 39 in FIG. 4B. As further shown in FIG. 4B, a portion of
one of the grid members of a supporting grid 38l is illustrated and
which is operable to support the aforementioned spaced apart pins
38f generally in the manner described in the aforementioned Patent
Application Publication. Alternatively, pins 38f may be embedded in
a conductive polymer member taking the place of components 38g and
38h and encapsulated by a nonconductive polymer structure taking
the place of parts 38l and 39, for example.
[0041] Referring briefly to FIGS. 7 and 8, the hinges 29 are
adapted to provide for at least partially counterbalancing the
weight of the door 32 or providing sufficient friction to enable
opening of the door 32 without the weight of the door impairing
operations to service the components supported on the door, such as
filter units 36 and 40 and charging unit 38. This is particularly
advantageous for filter units 20 which are mounted in a ceiling so
that when the door 32 is opened it does not drop rapidly to the
fully open position. In this regard, each of the hinges 29 includes
a first hinge part 29a adapted to be suitably secured to the
perimeter flange 26 of frame 24 and a second hinge part 29b
suitably secured to the door 32. A hinge pin part 29c, FIG. 8,
projects from hinge part 29a into a suitable bore in hinge part 29b
and is slidably retained therein by a digitally actuatable latch
part 29d. Actuation of the respective latch parts 29d enable
separation of the hinge parts 29b from hinge parts 29a so that the
door 32 may be moved with respect to the frame 24 by sliding the
door to the left, viewing FIG. 7, whereby the hinge parts 29a and
29b become disengaged for complete removal of the door 32 from the
frame 24, when desired. Alternatively, the hinges 29 may be
oriented to allow door 32 to be disconnected from frame 24 by
moving the door to the right, viewing FIG. 7. As mentioned
previously, hinges 29 may be provided such that when the hinge
parts 29b are rotated relative to the hinge parts 29a sufficient
friction or a counterbalancing force is exerted by each hinge to
retard or control movement of the door 32. Hinges 29 may be of a
type commercially available, such as from the Reell Precision
Manufacturing Corporation, St. Paul, Minn.
[0042] Door 32 is maintained in a so called closed position with
respect to chassis or frame 24 by respective digitally actuatable
latches 23, FIGS. 1 and 9. Grille 30 is provided with spaced apart
openings or recesses 30r, see FIG. 9, by way of example, at which a
digitally actuatable latch member 23a is disposed and may be
depressed downward, viewing FIG. 9, to engage and move a latch
member 23b so that a latch finger 23c secured thereto disengages
from a latch hook 24 suitably mounted on frame 24. Latch member 23b
is biased into the position for engagement of the finger 23c with
the hook member 24l by a suitable coil spring 23d supported by door
32. FIG. 9 is exemplary of both of the latches 23 and in response
to digital actuation of both latches the door 32 may be pivoted
with respect to the frame 24 between closed and open positions.
[0043] Referring to FIGS. 9A and 9B, an alternate embodiment of a
latch mechanism for maintaining the door 32 in a closed position is
illustrated. The latch mechanism illustrated in FIGS. 9A and 9B is
similar in some respects to the latch 23 but includes a modified
digitally actuatable latch member 23f engageable with a latch
member 23g including a finger 23h. Latch member 23g includes spaced
apart downwardly projecting legs 23j disposed for sliding
engagement with the door 32. A torsion coil spring 23k is mounted
on a hub 23l of latch member 23g and includes opposed tines 23m and
23n engageable with door 32 to bias the latch member into the
latching position shown in FIG. 9A. However, in response to digital
actuation of latch member 23f, latch member 23g is moved
downwardly, viewing FIGS. 9A and 9B, against the bias of spring 23k
to allow the door to be released from its closed position with
respect to the chassis or frame 24.
[0044] The main filter unit 36 is characterized by a generally
rectangular perimeter frame 36a, see FIG. 6, supporting stacked
filter elements like those disclosed in Patent Application
Publication No. US 2007/0039472 A1 and designated by numeral 36b in
FIGS. 2, 3 and 6. Frame 36a of filter unit 36 includes a handle
part 36c for use in moving the filter unit into and out of the slot
formed by the frame members 34 and 35, said slot being formed by
flanges 34b and 34c, see FIG. 4, and 35b and 35c, see FIGS. 5, and
7 also. A deflectable latch member 36d, FIG. 4, includes a latch
projection 36e engageable with a flange or wall forming the handle
38c of field charging unit 38, as shown. Accordingly, filter unit
36 may be retained on the door 32 by latching the filter unit to
the field charging unit 38 which is suitably retained in a slot
formed by the members 34 and 35 and delimited by the flanges 34c,
34d, 35c and 35d, see FIGS. 4, 5 and 7.
[0045] Referring briefly to FIG. 4A, an alternate embodiment of a
latch for latching the filter unit 36 in its working position
engaged with the field charging unit 38 is illustrated. As shown in
FIG. 4A, a digitally actuatable latch member 36k includes a stepped
latch part 36l and a digitally actuatable or engageable part 36m
which parts extend in opposite directions from a web part 36n. The
base of web part 36n includes a boss 36p which is supported for
pivotal movement about a pivot pin 36q and is biased into the
latching position shown by a torsion coil spring 36r. Accordingly,
latch member 36k engages the flange forming handle 38c of field
charging unit 38 in generally the same manner as provided for by
the latch 36d, 36e.
[0046] As shown in FIGS. 5 and 6, filter unit frame 36 includes
spaced apart elongated projections 36f extending along one side of
the frame and operable to receive a boss 35f, FIG. 5, slidably
therebetween so that the filter unit 36 may not be placed between
the support members or brackets 34 and 35 incorrectly. Frame 36a is
thus dimensioned such that it may not be placed inverted with
respect to door 32, thanks to the parallel projections 36f and boss
35f. Viewing FIG. 3, spaced apart electrical contact members 41a
and 41b are provided on filter unit frame 36a and are polarity
sensitive. Accordingly, the filter unit 36 is required to be
oriented in a pre-determined position, as shown in the drawings,
and should not be reversed or placed between the members 34 and 35
upside down. The aforementioned pre-filter 40 is also operable to
be disposed between the brackets 34 and 35 and suitably supported
thereby between flanges 34d and 34e, and between the flanges 35d
and 35e, FIGS. 4, and 5.
[0047] As shown in FIGS. 2 and 3, field charging unit 38 is also
provided with spaced apart electrical contact members 43a and 43b
which are polarity sensitive and are disposed, together with the
contact members 41a and 41b, in predetermined positions for
engagement with corresponding contact members disposed on a control
box or enclosure, generally designated by the numeral 42, see FIGS.
2, 3 and 10, for example. Control enclosure 42 is mounted on frame
24 between sidewalls 24c and 24d and preferably contiguous with
wall 24a. Suitable brackets 44a and 44b, FIG. 10, are supported on
or formed integral with opposed sidewalls 24c and 24d for
supporting control enclosure 42, as shown. Each of brackets 44a and
44b may be provided with suitable detent means 45, one shown, for
engagement with a corresponding projection on control enclosure 42
to assist in supporting the control enclosure when removable
fasteners 46, for example, are being secured to or removed from the
control enclosure.
[0048] Control enclosure 42 includes spaced apart electrical
contact elements 48a, 48b, 50a and 50b suitably supported thereon
as will be explained in further detail herein. Contact elements
48a, 48b, 50a and 50b are elastically deflectable and are
engageable with corresponding contact elements on the filter unit
36 and the field charging unit 38. Accordingly, when the door 30 is
moved to a closed position, as shown in FIG. 1, contact element 48a
engages contact member 41a, FIG. 3, contact element 50a engages
contact member 43a, contact element 48b engages contact member 41b,
and contact element 50b engages contact member 43b. As indicated in
FIG. 10, the contact elements 48a, 50a, 48b and 50b are marked with
the appropriate polarity markings. Thus, when door 32 is moved
between the position shown in FIG. 1 and a door open position,
electric power to the filter unit 36 and the field charging unit 38
is interrupted. Still further, as will be described hereinbelow,
electrical power is also cut off with respect to the contact
elements 48a, 48b, 50a and 50b mounted on the control box or
enclosure 42 so that these contact elements are de-energized.
[0049] Referring now to FIGS. 13, 14 and 15, control enclosure 42
includes opposed sections defining spaced apart enclosure spaces 51
and 52 for receiving certain electrical components of the controls
for the system 20, including a circuit board 53 and a power supply
or transformer 54. Suitable heat sinks, not shown, may be disposed
in space 51 also for maintaining a suitable operating temperature
for power supply 54. A suitable cover 42a is operable to cover the
enclosure 42 including the spaces 51 and 52. Enclosure 42 includes
an intermediate recessed portion 42b forming a chase, FIG. 13, to
provide clearance for handle portions 36c and 38c, FIG. 3, of the
filter unit 36 and field charging unit 38 when the door 32 is moved
to a closed position. Enclosure 42 may be formed in multiple parts
suitably secured together by intermediate section 42b.
[0050] Contact elements 48a, 48b, 50a and 50b are supported on
control enclosure 42 in a manner as illustrated in FIGS. 13 through
15. By way of example, viewing FIG. 15, contact elements or members
48b and 50b are suitably supported on enclosure 42 by respective
bosses 42f, one shown, formed integral with an enclosure bottom
wall 42g, FIG. 15, whereby contact member 50b is shown supported by
a boss 42f, by way of example, and projecting through a slot 42h in
wall 42g to assume the working position illustrated in FIG. 10.
Contact elements 48b, 50a and 48a are supported in a manner
virtually identical to that illustrated in FIG. 15. Each pair of
contact elements 48a, 50a and 48b, 50b is also protected by
respective removable covers 56a, and 56b, FIGS. 13 through 15.
Covers 56a and 56b are mirror image parts or are otherwise
configured to prevent misplacement and are each retained in
engagement with enclosure 42 by suitable fasteners, such as machine
screws 58, one shown in FIG. 15 for cover 56a.
[0051] As shown by example in FIG. 15, covers 56a and 56b are each
also provided with a top wall 60 and spaced apart depending
endwalls 61, 62 and 63, 64, which fit over upstanding fins 42j as
shown. This arrangement of the covers 56a and 56b and the fins 42j
provides isolation of electrical charges imposed on the contact
elements 48a, 50a, 48b and 50b from other control components. FIG.
15 is a composite section view illustrating the manner in which
each of the contact elements 48a, 48b, 50a and 50b is supported on
the enclosure 42 and how these elements are covered by the contact
element covers 56a and 56b. Suitable clearance holes 42l may be
provided in the enclosure 42 for receiving fasteners which may be
used to secure the frame 24 to a suitable cross member, not shown,
forming part of wall framing for receiving and supporting the frame
24.
[0052] As shown in FIG. 16, control enclosure 42 includes a
suitable electrical connector part 42k supported thereon for
connection to a source of electrical power not shown for the filter
unit 20. Respective, spaced apart integrally molded hooks 42m may
be provided on enclosure 42, as illustrated in FIG. 16, for
training electrical conductors along one side of the enclosure 42
to minimize the chance of such conductors dangling in the flow path
of air flowing through the return air duct 21 when the filtration
system 20 is installed in its working position shown in FIG. 1.
[0053] Referring now to FIGS. 10 and 11, the control enclosure 42
is adapted to support user operable control switches including a
main power on-off switch 62 and additional switches 64, 66 and 68
which project through suitable openings in enclosure wall portion
42s. Switches 64, 66 and 68 are, for example, operable for
inputting selected control operating features, such as for
selecting a minimum or maximum high voltage condition, a reminder
to service or change the pre-filter 40 and a reminder to service
the filter unit 36, for example. A seven segment visual display 70
is also provided for use in selecting the above-mentioned
parameters. Still further, a visual indicator 72 is provided to
indicate the status of the filtration system 20, that is, on versus
off and/or a need to service the system 20. The switches 62, 64,
66, 68, the display 70 and the indicator 72 may be mounted on a so
called daughter control board 74, FIGS. 13 and 16, supported within
the enclosure 42 and adjacent wall portion 42s. Suitable
elastomeric buttons, not shown, may cover the switches 62, 64, 66
and 68 to prevent unwanted contact with control board 74. As shown
in FIGS. 1 and 12, an actuator 76 for the switch 62 is supported by
the grille 30, as indicated, and includes an arm 76a engageable
with the switch 62, see FIG. 12, when door 32 is in the closed
working position. Actuator 76 is preferably formed of a somewhat
resilient electrically nonconductive material. As further shown in
FIG. 12, switch actuator 76 includes a translucent curvilinear rim
part 76b which is operable to transmit light from the visual
indicator 72 therethrough for observation by a user of the
filtration system 20 without opening the door 32. Accordingly, a
user of the filtration system 20 may energize and de-energize the
system without opening door 32, observe whether power is being
supplied to the system and/or observe if there is a need to service
the system.
[0054] Referring further to FIG. 11, the control system for the
filtration system 20 includes a so called interlock which
de-energizes the system when the door 32 is moved from a closed
position, as shown in FIG. 1, to an open position. A preferred
embodiment of the interlock includes a reed switch 80, FIGS. 11 and
17, preferably mounted adjacent to or on the daughter control board
74 or on or adjacent to circuit board 53. The reed switch 80 is in
proximity to a magnet 82, FIG. 3, when the door 32 is in the closed
position, which magnet may be mounted on the door 32. Accordingly,
when the door 32 is moved from its closed position, as shown in
FIG. 1, to an open position, as shown in FIGS. 2 and 3, magnet 82
moves out of range of the reed switch 80 thereby causing the reed
switch to open and interrupt power to the filtration system 20.
Alternatively, the magnet 82 may be mounted on the grille 30 in the
same general location such that, when door 32 or the grille alone
is moved, reed switch 82 will open.
[0055] Referring now to FIG. 17, there is illustrated a schematic
block diagram of a control system 84 for the filtration system 20,
including the circuit board 53, the power supply 54, and the
daughter board 74. Visual indicator 72 is shown mounted on board 74
in the diagram of FIG. 17, as well as switch 62, the display 70 and
the switches 64, 66 and 68. Power for the control system 84 is
typically received from an external 24 volt AC transformer
connected to or associated with a unit of air conditioning
equipment with which the return air duct 21 is associated. A power
source, such as a transformer 88, is indicated schematically in
FIG. 17. The control system 84 is also adapted to receive control
signals from a thermostat or other control circuit 90 associated
with the aforementioned air conditioning apparatus such that, when
a call for "heat", or "cooling" or "fan only" is generated by the
control circuit 90, signals are sent via conductors 92 or 94 to a
conditioning circuit 96 which is connected to a suitable
microprocessor 98 forming part of control system 84, as shown in
FIG. 17.
[0056] Microprocessor 98 is connected to daughter circuit board 74
via a suitable signal conditioning and transmission interface
circuit 100. Power input through the control circuit 84 is by way
of transformer 88 and a fused conductor 89 and conductor 91
connected to power supply 54 by way of the aforementioned interlock
which includes the reed switch 80 as shown in FIG. 17. As shown in
FIG. 17, microprocessor 98 also receives input signals from a zero
crossing sensor 102, an input voltage monitor 104, a high voltage
power supply input current monitor 106, a high voltage monitor 108,
a high voltage setting circuit 110 and a programming header 112.
Regulated high voltage power is supplied by power supply unit 54 to
the field charging unit 38 and the filter unit 36 by suitable
electrical connections including the contact elements associated
with the respective units and with the control box or enclosure 42,
as described above. The control system 84 may be similar in some
respects to the control system described in U.S. Patent Application
Publication No. US2007/0039462 A1 by Helt et al., published Feb.
22, 2007, and assigned to the assignee of the present invention.
The subject matter of Patent Application Publication No.
US2007/0039462 A1 is also incorporated herein by reference.
[0057] Referring now to FIGS. 18 and 19, another preferred
embodiment of an air filtration system in accordance with the
invention is illustrated and generally designated by the numeral
120. The filtration system 120 is similar in many respects to the
system described in Patent Application Publications US2007/0039462
A1 and US2007/0039472 A1 identified hereinabove. The system 120
includes a support frame 122 characterized as a substantially
u-shaped sheet metal member having a somewhat shallow channel
shaped cross section and comprising a bottom wall 124 and opposed
sidewalls 126 and 128. Sidewalls 126 and 128 are provided with
suitable elongated parallel guiderails for supporting a primary or
main filter unit 130 corresponding generally to the filter unit 36,
a field charging unit 132 corresponding generally to the field
charging unit 38 and a suitable pre-filter 134 corresponding to the
pre-filter 40. Accordingly, the filter unit 130, the field charging
unit 132, and the pre-filter 134 may be supported by the frame 122
in a manner substantially like that of the filter system 20. Frame
122 includes a perimeter frame member 138 suitably secured to the
sidewalls 126 and 128 and adapted to support a door assembly 140
for retaining the filter unit 130, the field charging unit 132 and
the pre-filter 134 in assembly with the frame 122.
[0058] Door assembly 140 includes a base plate 142 FIG. 19,
including spaced apart retainer tabs 144 and rotatable latches 146
for releasably connecting the door to the perimeter frame 138.
Spaced apart sets of electrical contact elements 150, 152 and 154
cooperate with the filter unit 130 and the field charging unit 132
in substantially the same manner as described in the aforementioned
Patent Application Publications which are incorporated herein by
reference. Door assembly 140 also comprises an enclosure for a
control circuit and components thereof substantially like that
illustrated in FIG. 17 or like that disclosed in Patent Application
Publication US2007/0039462 A1. The filter system 120 is
advantageous for retrofitting an improved filter system in
accordance with the invention to ductwork and in locations other
than an inlet to a return air duct, for example.
[0059] Preferred embodiments of the invention have been described
herein in sufficient detail, it is believed, to enable one skilled
in the art to practice the invention. Conventional engineering
materials and practices may be used to construct the embodiments of
the invention, except as otherwise described herein or in the
documents which are incorporated herein by reference. Although
preferred embodiments of the invention have been described in
detail, those skilled in the art will also recognize that various
substitutions and modifications may be made without departing from
the scope and spirit of the appended claims.
* * * * *